A saccade is a rapid, jerking movement, or the act of pulling up a horse quickly with a strong pull of the reins.

Rapid eye movement to redirect the line of sight.

a rapid, jerky movement of the eyes between positions of rest.

An eye's jump as it reads

Commonly, nystagmus is defined as rapid, repeated movements of the eyes. Clinically, physiological nystagmus is a type of eye movement characterized by alternating slow phase movements in one direction and Saccade-like quick phases in the other direction.